USER EQUIPMENT AND CODEBOOK SEARCH METHOD FOR 4TX DUAL CODEBOOK (RAN1)

摘要

An enhanced Node B (eNB) for precoding is generally described. In some embodiments, a first precoding-matrix indicator (PMI) and a second PMI is received on an uplink channel from user equipment (UE). Symbols for multiple-input multiple output (MIMO) beamforming may be precoded by the eNB using a precoder matrix recommended by the first and second PMIs, for a MIMO downlink orthogonal frequency division multiple access (OFDMA) transmission. The first PMI and the second PMI are calculated by selecting a representative codeword that is indexed by i1 and i2 for a plurality of 2TX constituent beams indexed by k to define, from the plurality of 2TX constituent beams, the 2TX constituent beam that provides the best system evaluation metric. The i1 index for wideband and the i2 index for each subband are identified from the defined 2TX constituent beam.